speed of light

American  

[speed uhv lahyt] / ˈspid əv ˈlaɪt /

noun

1. Physics, Optics. a fundamental universal constant, the speed at which light and all forms of electromagnetic radiation travel in a vacuum, standardized as 186,282.4 miles per second (299,792,458 meters per second).

   The speed of light, often represented by the letter c, figures prominently in modern physics, as in Einstein’s famous equation E = mc2, which expresses the relation between mass (m) and energy (E).

2. an extremely fast rate.

   They gobbled those appetizers up at the speed of light.

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Etymology

Origin of speed of light

First recorded in 1820–25

Example Sentences

Mr. White claims it may be possible to create a “warp drive” that would propel spacecraft faster than the speed of light by distorting spacetime using a field of negative energy.

From The Wall Street Journal

Here, E again represents energy, m is the particle's mass, and c is the speed of light.

From Science Daily

We see everything through a new lens; change now happens at the speed of light.

From BBC

Now, the latest artificial-intelligence bottleneck is optical interconnects, or the high-speed systems that allow massive chip clusters to communicate at the speed of light.

From MarketWatch

The ripples move through space at the speed of light, similar to the circular waves that spread across water after a stone is dropped into a pond.

From Science Daily